Enhance cache modes in resource loading

- Unify documentation, hoping to clear misconcepctions about about propagation of the cache mode across dependant loads.
- Clarify in docs that `CACHE_MODE_REPLACE` now also works on the main resource (from #87008).
- Add two recursive modes, counterparts of `CACHE_MODE_REPLACE` and `CACHE_MODE_IGNORE`, since it seems some need them (see #59669, #82830).
- Let resources, even loaded with one of the ignore-cache modes, get a path, which is useful for tools.

core/core_bind.h

@@ -63,9 +63,11 @@ public:
 	};
 
 	enum CacheMode {
-		CACHE_MODE_IGNORE, // Resource and subresources do not use path cache, no path is set into resource.
-		CACHE_MODE_REUSE, // Resource and subresources use patch cache, reuse existing loaded resources instead of loading from disk when available.
-		CACHE_MODE_REPLACE, // Resource and subresource use path cache, but replace existing loaded resources when available with information from disk.
+		CACHE_MODE_IGNORE,
+		CACHE_MODE_REUSE,
+		CACHE_MODE_REPLACE,
+		CACHE_MODE_IGNORE_DEEP,
+		CACHE_MODE_REPLACE_DEEP,
 	};
 
 	static ResourceLoader *get_singleton() { return singleton; }